New Tab Page Brave Together link and prompt should only show on nightly

[petemill]

...and for regions where Brave Together is supported.

Follow-up to the feature introduced in #12776

[kjozwiak]

@brave/legacy_qa once this lands and we do channel migrations, we should get both 1.20.x & 1.21.x to make sure that Brave Together is only available on 1.22.x (Nightly).

[LaurenWags]

Per #13905 (comment) marking as QA/blocked until channel migrations are done so we can check across all versions.

[GeetaSarvadnya]

Verification passed on

Brave | 1.20.100 Chromium: 88.0.4324.146 (Official Build) (64-bit)
-- | --
Revision | 406dc88511162d6598242f2c709be1414a042fb0-refs/branch-heads/4324@{#2088}
OS | Windows 10 OS Version 2004 (Build 19041.746)

• Verified the test plan from New Tab Page WebUI: restrict Together item to supported channel and region brave-core#7787 and description from Add link to Brave Together on New Tab Page #12776 (comment)

Nightly channel - 1.22.6

• Ensured that brave together link and the prompt is shown in New Tab Page in the nightly build ONLY
  
  

• Ensured that brave together link and the prompt isn't shown in New Tab Page in Dev/Beta/Release channels

Dev channel - 1.21.45

Beta channel - 1.21.44

Release channel - 1.20.100

Verified using

Brave	1.22.6 Chromium: 89.0.4389.40 (Official Build) nightly (x86_64)
Revision	2c2ed83cd507b23e4845edd09a7d1dfc727daf4b-refs/branch-heads/4389@{#602}
OS macOS Version 11.2 (Build 20D64) and `Nightly`, `Dev`, `Beta`, `1.20.100` builds

Scenario One: Nightly, en-USlocale/region

1. clean install (new profile) of Nightly

Brave	1.22.6 Chromium: 89.0.4389.40 (Official Build) nightly (x86_64)
Revision	2c2ed83cd507b23e4845edd09a7d1dfc727daf4b-refs/branch-heads/4389@{#602}
OS	macOS Version 11.2 (Build 20D64)

2. launch Nightly
3. open the new-tab-page ("NTP")
4. confirm presence of Brave Today promo panel

Nightly

Scenario Two: Nightly, other regions & languages

1. (on Big Sur) open the Apple menu, choose System Preferences, Language & Region, General tab
2. click the + button, under "Preferred languages", add either German, Greek, or something of your choosing; remove your previous default language
3. still on the General tab, choose Greece or Germany (or your choice) from the appropriate region, and follow system prompts
4. restart macOS
5. launch Nightly
6. confirm presence of Brave Together promo panel

Scenario Three: {dev, beta, 1.20.100 (RC) builds}

1. clean-install and new profile for any and all of the following builds: dev, beta, and 1.20.100
2. launch the browser
3. open the new-tab page
4. confirm absence of promo panel for Brave Together

Dev	Beta	1.20.100
Brave 1.22.2 Chromium: 88.0.4324.146 (Official Build) nightly (x86_64) 406dc88511162d6598242f2c709be1414a042fb0-refs/branch-heads/4324@{#2088}	Brave 1.21.45 Chromium: 88.0.4324.146 (Official Build) dev (x86_64) 406dc88511162d6598242f2c709be1414a042fb0-refs/branch-heads/4324@{#2088}	Brave 1.21.44 Chromium: 88.0.4324.146 (Official Build) beta (x86_64) 406dc88511162d6598242f2c709be1414a042fb0-refs/branch-heads/4324@{#2088}

---

Verification passed on

Brave	1.20.101 Chromium: 88.0.4324.152 (Official Build) (64-bit)
Revision	6579930fc53b4dc589c042bec9d0a3778326974d-refs/branch-heads/4324@{#2106}
OS	Ubuntu 18.04 LTS

• Verified the test plan from New Tab Page WebUI: restrict Together item to supported channel and region brave-core#7787 and description from Add link to Brave Together on New Tab Page #12776 (comment)

Brave	1.20.101 Chromium: 88.0.4324.152 (Official Build) (64-bit)
Revision	6579930fc53b4dc589c042bec9d0a3778326974d-refs/branch-heads/4324@{#2106}
OS	Ubuntu 18.04 LTS

Brave	1.21.47 Chromium: 88.0.4324.152 (Official Build) beta (64-bit)
Revision	6579930fc53b4dc589c042bec9d0a3778326974d-refs/branch-heads/4324@{#2106}
OS	Ubuntu 18.04 LTS

Brave	1.21.45 Chromium: 88.0.4324.146 (Official Build) dev (64-bit)
Revision	406dc88511162d6598242f2c709be1414a042fb0-refs/branch-heads/4324@{#2088}
OS	Ubuntu 18.04 LTS

Brave	1.22.9 Chromium: 89.0.4389.40 (Official Build) nightly (64-bit)
Revision	2c2ed83cd507b23e4845edd09a7d1dfc727daf4b-refs/branch-heads/4389@{#602}
OS	Ubuntu 18.04 LTS